Digital BW, The Print

Don't forget that you can use all 4 blacks when printing on matte 
paper. That may help you smooth out any rough spots down near full 
black. To smooth out the highlights, skip the medium black, and use llb 
and a mix of llb+glop for your lightest shade. A 1:1 mix might be just 
what you need. Then the PK would help fill in the mid tones. I'm not 
sure how well this would work for glossy, but it should be fine for 
matte (with the right mixing in the RIP).